ref: http://dc0d32.blogspot.com/2010/06/real-mode-in-c-with-gcc-writing.html
write bootloader by c (practice)

bhp.S - enter x86 protected mode
cb.c  - c bootloader example and test real mode c pointer.
bh.asm - nasm bootloader code
bh.s - gas bootloader code

The directory programs are for presentation of MOSUT 
(http://code.google.com/p/mosut/ - 作業系統之前的程式 & x86 保護模式 /).